1. Field
The present invention relates to a cleaner.
2. Background
A cleaner is an apparatus that suctions dust from floor. In general, the cleaner includes a suction device having a suction port for air suction and a main body connected to the suction device via a hose defining an air suction channel. The main body is provided with an air suction fan for generating negative pressure to suction air through the suction port, and the suction device or the main body is provided with a dust collector for collecting dust introduced through the hose.
The suction device is moved by a user, and the main body follows the suction device. Generally, the main body is moved by tension applied from the hose. In recent years, there has been developed a cleaner including a motor mounted in the main body for rotating wheels of the main body such that the main body can move for itself.
In addition, there is known a cleaner including an ultrasonic transmitter provided at the suction device and an ultrasonic receiver provided at the main body such that the main body actively follows the suction device based on ultrasonic waves received through the ultrasonic receiver. However, the ultrasonic receiver may receive ultrasonic waves reflected by an obstacle or a wall within a cleaning zone with the result that the main body may not properly follow the suction device.